Internal combustion engines



F. L. PRESCOTT ETAL 2,911,964

INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 1 Nov. 10, 1959 Filed Aug.17. 1955 l'l l l INVENTORS FORD L. PRE S COTT EDWARD A. HULBERT BY ATTORNov. 10, 1959 Filed Aug. 17, 1955 3 Sheets-Sheet 2 INVENTORS FORD L.PRESCOTT By EDWARD A. HULBERT ATTORN S Nov. 10, 1959 Filed Aug.

F. 1.. PRESCOTT T L INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 3INVENTORS FORD L. PRESCOTT BY EDWARD A.HULBERT ATToRN S United StatesPatent INTERNAL COMBUSTION ENGINES- Application August 17, 1955, SerialNo. 528,902

8 Claims. (Cl. 123 -41.65)

This invention relates to an internal combustion engine construction andmore particularly to the so-called H-type two-stroke cycle engine,generally used in military tanks,

rail cars, and power generators and having an improved structuralcompactness and operating efliciency.

The engine structure. here disclosed relates generally to' H-typeengines in which cylinders on each side 'of an engine case are conjoinedby connecting rods to a central crankshaft. In some cases, separatecrankshafts for the separated cylinders are further conjoined toanother,'the output, crankshaft. In the instant invention, the cylindersare arranged vertically, though they may be disposed horizontally, ifdesired, each cylinder having two opposed pistons operable therein. Thepistons are connected to rocker arms which are in turn connected bylinks to the crankshaft. A single engine unitcomprises a pair ofparallel cylinders with four operating pistons therein conjoined bysuitable rocker arm linkage to a single centrally arranged transversecrankshaft. Multiple engine units may be arranged in an engine case orhousing, one by the other, all serving a single transverse cranckshaft.

There are some especial advantages in the instant construction which areamong the objects ofthe invention. As will be seen in the drawings andnoted in the specific description given below, the engine unit is madeextremely compact, uniform and symmetrical. All of these characteristicsimprove the efficiency and expand the utility of the engine. There areno open or void spaces, no lost or waste areas that consume or requirelimited space in the engine chamber of vehicles. The cubical'content ofthe engine is held to a minimum, achieving more horsepower per unitweight and volume. v v v A further and highly desirable advantage isthat the instant invention provides only a single crankshaft to serveany four or multiple of four pistons. This structural feature markedlyreduces engine noise, chatter and rattle, particularly at low or idlingspeeds, as compared to current engine constructions in which duel gearedcrankshafts are required. In crankshaft arrangements of the latter type,engine noise frorn'gearing is almost impossible to eliminate especiallyat idling and low speeds. As the engines grow older in use, thenoiseincreases and efficiency decreases. Such construction is completelyabsent from the instant invention.

It is therefore an object of the invention to provide in an internalcombustion engine an arrangement of parallel cylinders on each side ofan engine crankcase and preferably separate therefrom; to provide dualopposed pistons in each cylinder therein; to provide a single outputcrankshaft operatively connected to all pistons; to provide anintegrated engine structure of reduced cubic content; and to provide aneconomical, practical'and efiicient engine structure embodying theseinventive improvements. I n a Additional objects and structural featuresof the invention will become more'apparent from the description givenbelow. For a visual understanding'of the'invenf tion, reference is madeto'the accompanying drawings'in which like p'arts are referred to bylike reference numerals throughout the several views illustrating apreferred embodiment of the invention, and in which- Fig. 1 is a sideelevational view of the engine embodying the inventive construction.

Fig. 2 is a vertical cross sectional view through a single engine unitof the engine of Fig. 1.

Fig. 3 is a top plan view of the engine of Fig. 1, partially in section.

As indicated in the drawings, the engine structure 10 comprises acrankcase 11 (see Fig. 2) to which an upper rocker arm housing 12a and alower rocker arm housing 12b are secured by studs and nuts or othermeans as at 13. Cylinders 14 are secured by studs or bolts 15 to eitherthe upper or lower housing aforesaid as shown and the free end ispreferably slidably mounted at the other housing within 0 ring sealguides 14a. An upper housing cover 16 and a lower housing cover or pan17 are installed on the upper and lower rocker arm housings respectivelyby bolts 18 or other suitable means.

An accessory gear case 20 of conventional construction is installed atone end of a cranckshaft 21 which exscribed presents a compact, roughlycubical shape, due

to the position of the cylinders and rocker arm housings relative to thecrankcase. I

A fuel injector 30 is mounted in each cylinder wall 25 to supply fuelinto the midpoint of a cylinder bore 31.

In addition, each cylinder is provided with an annular in- 7 takepassage 32 and an annular exhaust passage 33.

Each passage is open to a port 34 opening into the cylinder bore 31.

Two opposed reciprocating pistons 38 are operable in each cylinder bore31, the fuel charge from the fuel injector 30 being directed betweenthem, into the combustion chamber 38a formed thereby. A link member 46is preferably rigidly secured to a piston pin 41 conventionally pivotedin each piston 38, and its free end is pivotally secured to an end 42aof a rocker arm 42. The other end 42b of the rocker arm 42 is pivotallysecured to a connectingrod 43, which in turn is supported by a crankpin44 of the crankshaft 21. This connecting rod is preferably of a slipperrod type, permitting it to pivot relative to the crankpin while stillbeing secured thereto,

and also permitting relative angular displacement of the slipper rodsconnected to the same crankpin. v

The rocker arm 42 is pivotally mounted on a shaft 50 carried in a pintlemeans 51. Through-bolts 51a pass from the upper block of pintle means 51through the lower block, and are adapted to take the explosion force ofthe-pistons 38 acting on the rocker arms 42.

It will be noted that in a single engine unit of two spaced parallelcylinders 14, the upper piston 38 of one cylinder is connected by links40, rocker arms 42, com necting rods 43 and crankshaft 21 to the lowerpiston of the other cylinder, whereby the two pistons reciprocate in Thecrankcase 11 is a. separate component structure I V and is spaced fromthe cylinders 14 and is substantially central ,of the engine, runningaxially with the crankshaft.

conventional opposedpiston engines, makes possible a through-scavenge oruniflow scavenge of the exhaust gases from the cylinder. -One piston ofa cylinder serves as an intake valve and the other piston as an exhaustvalve. The connecting rods to the pistons ofone cylinder are placed atan average or center line angle of 160 to '175 degrees to each otherrather than at 180 degrees, by offsetting the crankshaft. relative tothe rocker arm ends 42b. The two cranks of the crankshaft are shownasangularly spacedsubstantially 180 degrees. In operation, the offsetanglecauses one piston to lead. the other, in the same cylinder, by aphase angle of to degrees, of crankshaft rotation. The leading pistonserves as the exhaust valve and the lagging or following piston serves.as the intake valve. is thus provided between exhaust opening and intakeopening, and a supercharge periodis provided betweenexhaust closing andintake closing. This arrangement serves to thoroughly scavenge and alsoto supercharge the cylinder, resulting in high power output and low fuelcon- A blow-down period 1. In an opposed piston type internal combustionengine comprising a plurality of separable component engine structures;namely, a pair of engine cylinder structures, opposed pistons operablein each of said engine cylinder structures, a crankcase structure spacedfrom and disposed intermediate said pair of engine cylinder structures,a crankshaft supported by the aforesaid crankcase structurepand rocker:arm housing structures secured to opposite faces of said crankcase, saidrocker arm housing structures being-respectively disposed in parallelplanes extending parallel to the crankshaft'axis having lateralextensions overlying the ends of said cylinder structures sumption. Itwill be observed that varying the angular position of the cranksrelative to each other and different from the 180 degree spacing asrecited above will result in varying the phase angle between the pistonsoperable in the same cylinder. In practice the cranks are spacedgenerally about 170 to 180 degrees apart.

The engine is lubricated by means of a forced lubrica tion system whichpasses the lubricant from rocker arm shaft 50 to the link member 40, thepiston pin 41, the piston 14 and up the cylinder bore 31. Thelubrication system is such as is well known in the art and has beenpreviously applied in air cooled engines. Oil coolers 23, forming acomponent part of the lubricating system, are arranged at the twoflywheel end corners of the engine.

The flywheel and cooling fan assembly 22 isenclosed by a cooling fanhousing secured to the end of the crankcase opposite the accessory gearcase, and comprises a crankshaft mounted flywheel 70, to the peripheraledge of which is affixed a series of spaced vanes 72 comprising thecooling fan unit 74. Air drawn in is passed past the cylinder aircooling fins 26 between baffles 78 into the space lying between thecylinder and the engine crankcase, indicated as a whole by referencecharacter 101, where the air may sweep past the wall of the crankcase 11from which it is drawn into the lower unit 74 and is passedout of theengine through a discharge outlet 80, as indicated by the arrow in Fig.3. Likewise cooling air is drawn through the cooler 23 and thence di--with the pistons and their associatedlinkage provide high-- ly efficientpower transmission. Reduced engine noise is a direct result of thesingle crankshaft arrangementachieved by the instant engine structure.The absence of valves and their attendant camshaftsandgearing coupled tothe crankshaft contributes to space saving and efficiency;

Having described our invention, it will be apparent to those skilledin'the art to which this invention pertains that various modificationsand changes may be made" without departing from'the spirit of theinvention or from the scope of the appended claims.

We claim;

and providing cylinder supporting means, rocker arm mechanisms'ineachofsaid rocker arm housing structures and operable in planes containingthe cylinder axes and normal to the crankshaft axis, said rocker armmechanisms connected with the pistons in said cylinder structures andwith said crankshaft, each .ofsaid cylinder structuressecured to thelateral extensions of said rocker arm housing structures.

2. An opposed piston type internal combustion engine comprising aplurality of separate component engine structures; namely, a pair ofengine cylinder structures, op-

posed pistons'operable in each of said engine cylinder structures, acrankcase structure spaced from and disposed intermediatesaid pair ofengine cylinder structures, a crankshaft. supported by the aforesaidcrankcase structure, rocker .arm housing structures secured to oppositefaces of said crankcase which. are respectively disposed in parallel.planes extending parallel to the crankshaft axis and are laterallyextended to overlie the ends of said engine cylindenstructures, rockerarm mechanisms in each of said rocker arm housing structures andoperable in planes containing the cylinder axes and normal to thecrankshaft axis, said rocker arm mechanisms connected with the pistonsin said cylinder structures and with said crankshafheach of saidcylinder'structures bolted rigidly to one of said rocker arm housingstructuresand anchored to said other rocker arm housingwith a slidingconnection permitting relative movement between said cylinder and saidlast mentioned rocker arm housing structure.

3. An opposed piston/type internal combustion engine comprising'aplurality of separate component engine structures; namely, a pair ofengine cylinder structures, opposed pistons operable in each of saidengine cylinder structures,'-a crankcase structure spaced from anddisposed intermediate said pair of engine cylinder structures, acrankshaft-supported by the' aforesaid crankcase structure, rocker armhousing structures secured to opposite faces of said crankcase which arerespectively disposed in parallel planes extending parallel to thecrankshaft axis and are laterally extended-to 'overliethe ends of saidengine cylinder structures,- -rocker arm mechanisms in each -of saidrocker arm housing structures and operable in planes containing thecylinder axes nad normal to the crankshaft-axis, said rocker armmechanisms connected with the pistons in said'cylinder structures andwith said crankshaft, each of said cylinder structures bolted rigidly tooneof said rockerarm housing structures and anchored to said otherrocker 'arm' housing with a sliding connec-'- tion permitting relativemovement between said cylinder and said last mentioned rocker armhousing structure; said sliding 'connectionbetween said cylinder androcker arm structure comprising -a circular opening telescopinglyreceiving the outer end portion of said cylinder whereby to provide asliding fit therebetween;

4. An opposedpiston'type internal combustion engine comprising 1a-plurality -of;separable component engine structures; namely, a pair ofengine cylinder structures, .opposed pistonsoperable-in' each of saidengine cylinder structures, a crankcase structure located substantiallymedially of and spaced from'said pair of engine cylinder structures, acrankshaft supported by said crankcase structure and dispose'dwith itsaxis normal to anengine plane containingtheuaxes of both said cylinderstructures, and

means connecting each of said opposed pistons of both said cylinderstructures to said crankshaft and comprising a rocker arm, a linkconnecting one end of the rocker arm to said piston and a connecting rodconnecting the other end of the rocker arm to said crankshaft, saidcrankshaft having a pair of cranks which are disposed substantially 180degrees out of phase, said connecting rods constructed and arranged toconnect one piston of the opposed piston assembly of one engine cylinderstructure and the diagonally located piston of the opposed pistonassembly of said other engine cylinder structure to the same crank ofsaid crankshaft, so that when said pistons of one engine cylinderstructure are at approximately the peak of their compression stroke, thepistons of said other engine cylinder structure are approximately at thebottom of their power stroke, a rocker arm housing structure secured toopposite parallel faces of the crankcase and having lateral extensionsof overlying the ends of both engine cylinder structures said lateralextensions providing cylinder supporting means, said rocker armspivotally supported by said rocker arm housing structures.

5. An opposed piston type internal combustion engine comprising aplurality of separable component engine structures; namely, a pair ofengine cylinder structures, opposed pistons operable in each of saidengine cylinder structures, a crankcase structure located substantiallymedially of and spaced from said pair of engine cylinder structures, acrankshaft supported by' said crankcase structure and disposed with itsaxis normal to an engine plane containing the axes of both said cylinderstructures, and means connecting each of said opposed pistons of bothsaid cylinder structures to said crankshaft and comprising a rocker arm,a link connecting one end of the rocker arm to said piston and aconnecting rod connecting the other end of the rocker arm to saidcrankshaft, said crankshaft having a pair of cranks which are disposedsubstantially 180 degrees out of phase, said connecting rods constructedand arranged to connect one piston of the opposed piston assembly of oneengine cylinder structure and the diagonally located piston of theopposed piston assembly of said other engine cylinder structure to thesame crank of said crankshaft, so that when said pistons of one enginecylinder structure are approximately at the peak of their compressionstroke, the pistons of said other engine cylinder structure areapproximately at the bottom of their power stroke, a rocker arm housingstructure secured to opposite parallel faces of the crankcase and havinglateral extensions overlying the ends of both engine cylinderstructures, said lateral extensions providing cylinder supporting meanspintle means carried by said rocker arm housing structure for rotatablysupporting each of said rocker arms, and tension bolt means for boltingtogether a pair of pintle means, one in each of said rocker armhousings.

6. In an opposed piston type internal combustion engine comprising apair of engine cylinder structures, opposed pistons operable in each ofsaid engine cylinder structures, a crankcase structure locatedsubstantially medially of said pair of engine cylinder structures, acrankshaft supported by said crankcase structure and disposed with itsaxis normal to an engine plane containing the axes of both said cylinderstructures, and means connecting each of said opposed pistons of bothsaid cylinder structures to said crankshaft, a fan housing secured toone end face of said crankshaft and having an air intake and exhaust, afan in said fan'housing and driven by said crankshaft and disposed tomove air generally in a direction parallel to the crankshaft axis, saidcylinder structures being spaced laterally from said crankcase structureto provide an air space, said cylinders having fins, and air bafflemeans associated with said finned cylinders to confine the air flow inheat transference relation with the cylinders, said fan operable toinduce air flow laterally past the cylinders and in heat transferencerelation with respect to the crankcase.

7. An opposed piston type internal combustion engine comprising a pairof engine cylinder structures, opposed pistons operable in each of saidengine cylinder structures, a crankcase structure located substantiallymedially of said pair of engine cylinder structures, a crankshaftsupported by said crankcase structure and disposed with its axis normalto an engine plane containing the axes of both said cylinder structures,and means connecting each of said opposed pistons of both said cylinderstructures to said crankshaft, a fan housing secured to one end face ofsaid crankshaft and having an air intake and exhaust, a fan in said fanhousing and driven by said crankshaft and disposed to move air generallyin a direction parallel to the crankshaft axis, said cylinder structuresbeing spaced laterally from said crankcase structure to provide an airspace, said cylinders having fins, and air baflle means associated withsaid finned cylinders to confine the air flow in heat transferencerelation with the cylinders, said fan operable to induce air flowlaterally past the cylinders and in heat transference relation withrespect to the crankcase, an oil cooler supported on said engine andhaving an air inlet and an air exhaust means, said oil cooler airexhaust means openly communicating with said air space between saidcylinders and said crankcase.

8. In an opposed piston type internal combustion engine comprising aplurality of separate component engine structures; namely, a pair ofengine cylinder structures, opposed pistons operable in each of saidengine cylinder structures, a crankcase structure spaced from anddisposed intermediate said pair of engine cylinder structures, acrankshaft supported by the aforesaid crankcase structures, and rockerarm housing structures secured to opposite faces of said crankcase whichare respectively disposed in parallel planes extending parallel to thecrankshaft axis and are laterally extended to overlie the ends of saidengine cylinder structures, rocker arm mechanisms in each of said rockerarm structures and operable in planes containing the cylinder axes andnormal to the crankshaft axis, said rocker arm mechanisms connected withthe pistons in said cylinder structures and with said crankshaft, a gearcase structure, and a cooling fan housing structure, said last twomentioned structures respectively secured to two other opposed faces ofthe crankcase structure lying in parallel planes extending normal to thecrankshaft axis, each of said cylinder structures secured to said rockerarm housing structures.

References Cited in the file of this patent FOREIGN PATENTS 918,281France Oct. 14, 1946

